FAKULTÄT DER CHEMISCHEN TECHNOLOGIE IN SPLIT
PERIODENSYSTEM DER ELEMENTE version 1.7
K
Englisch: Potassium
Französisch: Potassium
Kroatisch: Kalij
Deutsch: Kalium
Italienisch: Potassio
Ordnungszahl: 19
Elementgruppen: 1
Perioden: 4
Zustand (20 °C): fest
Potassium was discovered by Sir Humphry Davy (England) in 1807. The origin of the name comes from the Arabic word qali meaning alkali (the origin of the symbol K comes from the Latin word kalium). It is soft, waxy, silver-white metal. Fresh surface has silvery sheen. Quickly forms dull oxide coating on exposure to air. Reacts strongly with water. Reacts with water to give off flammable gas. Reacts violently with oxidants. Occurs only in compounds.
Elektronenkonfiguration: [Ar] 4s1
Relative Atommasse: 39.0983(1)
Oxidationszustände: +1
Elekronegativität: 0.82
Wärmeleitfähigkeit: 102 W/(m K)
Elektrische Widerstandskraft (20 °C): 6.15 μΩcm
Atomradius: 227.2 pm
Dichte (g/dm3): 862 (293 K)
828 (m.p.)
Atomvolumen (cm3/mol): 45.36 (293 K)
47.22 (m.p.)
Schmelzpunkt: 63.38 °C
Siedepunkt: 759 °C
Kritische Temperatur: 1950 °C
Bildungsenergie: 2.4 kJ/mol
Verdampfungsenergie: 79.1 kJ/mol
Zerstäubungsenergie: 90.14 kJ/mol
Potassium is found in minerals like carnallite [(KMgCl3).6H2O] and sylvite (KCL). Pure metal is produced by the reaction of hot potassium chloride and sodium vapours in a special retort. Used as potash in making glass and soap. Also as saltpetre, potassium nitrate (KNO3) to make explosives and to colour fireworks in mauve. Vital to function of nerve and muscle tissues. The price of 90.2 % pure potassium metal is 90.20 € for 5 g.
18Ar <= 19K => 20Ca
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Periodensystem der Elemente
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Letzte Änderung:
29.03.2003
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